In a gas turbine, a transition piece is provided between a combustor and a turbine. For example, Patent Literature 1 discloses a transition structure as shown in FIG. 6.
In the transition structure shown in FIG. 6, a transition piece 100 includes: a duct 101 including a circular inlet and an arc-shaped outlet; and an outer flange 102 and an inner flange 103, which protrude from the downstream end of the duct 101. The outer flange 102 is fixed to a turbine 110 by unshown bolts.
The duct 101 of the transition piece 100 is surrounded by a piece cover 130. The piece cover 130 is provided with bosses 131 intended for fixing the piece cover 130 to the duct 101. The bosses 131 are fixed to lugs (not shown) provided on the duct 101 by unshown bolts.